The invention is based on an apparatus having a control motor for intervention into a transmission device between an operating element and a control device that determines the output of a driving engine.
Various regulating operations for driving engines require an intervention into the transmission device between the operating element, such as a gas pedal, and the control device, such as a throttle valve in an Otto engine or an adjusting lever in a Diesel engine or the like. The regulation may be effected by regulating devices known per se, for instance to avoid slip between vehicle wheels driven by the engine and a road surface.
In a known apparatus of this type, the operating element is operatively connected to a first lever, for instance via a cable, and the control device is operatively connected to a second lever, for instance via a further cable. A restoring spring tends to urge the control device into a terminal position. A tension spring acts on the one hand on the first lever and on the other on the second lever, tending to press a stop of the first lever against a stop of the second lever. The effect of the tension spring is greater than the effect of the restoring spring. A control motor may also act upon the second lever, such that the second lever is rotated relative to the first lever, counter to the tension spring, and can thus move the two stops away from one another. On the rotation of the second lever relative to the first lever, the position of the control device can be varied relative to the position of the operating element. The control motor acts upon the second lever in the direction of the restoring spring, counter to the tension spring.
A distinction can be made between two operating states of the transmission device: an unregulated operating state, and a regulated state.
In the unregulated operating state, the control motor is not triggered. A particular position of the control device is associated with a particular position of the operating element. The control device follows the operating element in accordance with a predetermined transmission ratio.
In the regulated operating state, the transmission ratio is varied by the control motor. First, the operating element specifies a position. This position would be equivalent to a particular position of the control device in the unregulated operating state. In the regulated operating state, however, the control motor is triggered, which has the effect that the control device assumes a position different from the position in the unregulated operating state.
In the unregulated operating state, that is, when the control motor is not triggered, a rotor of the control motor must be jointly actuated when the operating element is actuated, in order to change the position of the control device. This requires greater actuating forces upon actuation of the control device. To avoid having to design a restoring spring with an overly great force, a proposal has been made that a free-wheel be installed between the control motor and the second lever. However, the free-wheel can lower the actuating forces in only one actuation direction.